Piston for engines



Dec. 11 1923.

c. E. HATCH PISTON FOR ENGINES Filed Feb. 24

mesa-u a wi h INVENTOI? Patented Dec. 11, 1923.

CHARLIE E. HATCH, OF DENVER, COLORADO.

PISTON FOR ENGINES.

Application filed February 24, 1922. Serial No. 538,906.

To all whom it may concern:

Be it known that I, CHARLIE E. HArcn, a citizen of the United States, residing at Denver, county of Denver, and State of Colorado, have invented certain new and useful Improvements in Pistons for Engines, of which the following is a specification.

The object of my invention is to provide a flexible skirted piston With rigidly and in dependently supported Wrist pin lugs, which will be an improvement over my former piston covered by my patent application filed December 2nd, 1921, Serial Number 519,453.

In my former piston th wrist pin lugs are separated from the skirt by openings through the skirt wall which extend partially about the wrist pin lugs The skirt is provided with a longitudinal cut and with a transverse cut in connection with said longitudinal cut, and also with an ex andlag ring within the lower extremity of said s irt.

This piston gives better results than any of my former pistons and when first installed did everything that could be wished.

But, structurally there seems to be a weak spot between the ends of the transverse cut, and the openings about the wrist pin lugs. After these pistons are run for some length of time this weak spot breaks through.

Thus both thrust faces of the skirt are then carried entirely by the one thrust face of the skirt, making a sceond weak spot where this thrust face connects with the head section of the piston. So far none of these second weak spots have broken through, though I am expecting it at any time, with the consequent wreck of an engine.

But, the breakage throu h these first mentioned weak spots natura ly suggets a construction in which the piston would be free to ive at these points.

I feel that probably one of the contributing causes of the breakage is the fact that on down center man automobile engine pistons are nearly ha f way out of the 'cylinder. With the internal expanding ring at the lower extremity of the skirt this naturally allows considerable working of the skirt in and out on each revolution, this expanding and contracting being localized at the above mentioned weak spots with the re sultant breakage.

I feel that this piston in a perfectly parallel cylinder of sufiicient length would give perfect satisfaction without breakage.

But, for a commercial piston that will give satisfaction wherever used, a construc tion is required that does not have this weak ness.

Therefore, in my present piston I have made two changes which, in the light of my experience should give me a truly perfect construction.

The first change in that the expanding ring is placed within the skirt just below the wrist pin lugs, so that in most engines this ring will be above the lower extremity of the cylinder on down center and thus reduce the tendency of the skirt to work in and out on each revolution; This also gives another advantage in selling and shipping the pistons partly finished, as will appear below.

In the second change the transverse cut is extended till it connects with the openings about the wrist pin lugs, which allows flexibility right at the point where my breakage shows it should be allowed; and the skirt, either side of the longitudinal cut is supported by a direct connection with the head of the piston.

This gives the requisite strength while at the same time allowing flexibility just where it is required.

In the drawings, Figure 1 shows a side elevation of my new piston looking at right angles to the wrist pin bore; Figure 2 shows a side elevation of the split half of my piston, lookin Figure 3 sl ows a partial vertical section of my new piston; Figure 4 shows a horizontal section through the center of the wrist -pin bore; Figure 5 shows a horizontal section on the line 5-5 of Figure 1, and Figure 6 shows a side elevation similar to Figure 1 of the piston when partly finished and in condition for shipment. The wrist pin lugs 1 are rigidly attached to the head 1 by the external ribs 2, and the internal rib 3, and are separated from the skirt 4 by the apertures 4. Either two or three ribs ma be used in place of the single rib 3, if desired, just so the construction in any case is strong eriplugh so that no breakage will ever be pos- 81 e.

The skirt 4 is provided with the single cut 5 connecting at its upper end with the transverse cut 6. The transverse cut 6 connects at its ends with the apertures 4 about the wrist pin lugs 11,

in line with the wrist pin bore:,

The wrist pin lugs 1 may be provided with bushings, or the wrist pin may be immovably secured in the luvs 1, with the bearing in the connecting rod end if desired.

The expanding ring 7 fits in the internal ring groove in the skirt 4 just below the apertures 4.

The slightly thicker portion forming an internal ring 8 at the lower extremity of the skirt 4 is provided so that it may receive the centered plug used in finishing pistons.

The ribs 9 and the posts 10 connect the skirt 4 on either side of the transverse cut 5, with the head 1" of the piston.

The posts 10 may be made as one post with the ribs 9 connecting thereto if desired; and the shape, size and exact location of the ribs 9 and the posts 10 may be altered to suit the ideas of any particular designer and the requirements of the engine in question. But in any case the results will be the same in that the ribs and posts form a connection between the skirt (on either side of the longitudinal cut) and the piston head, giving a construction that supports the skirt not only with flexibility. but with strength as well.

Heretofore it has been quite a problem as to just how my pistons could be partly finished and then shipped to repair men throughout the country to be finally fitted to the engines being repaired.

The skirt can not be split before final finishing; and the steel expanding rings are quite stiff and considerable care, as well as the proper equipment must be used to put them in place so that they will expand the piston and maintain it truly round. So it is desirable to send out the partly finished pistons with the expanding rings already in place. Heretofore, if this were done there would be little chance for repair men to properly center the skirt end of the piston for finishing, because of the expanding ring right at the lower end of the skirt.

But. in my present piston, as the expanding ring 7 is some distance up from the lower extremity of the skirt, this difficulty does not arise.

The skirt end may be centered by pressing a centered plug into the internal ring 8, and

the piston may then be finished.

When my present piston is shipped in an unfinished condition as shown in Figure 6, the longitudinal cut 5 will not quite connect with the transverse cut 6, nor will it extend quite to the lower extremity of the skirt t.

nd the apertures 4* will not quite connect with the transverse cut 6. This leaves the piston in effect solid, at least as regards the fine finishing cuts still required in its fitting.

When the desired size is obtained, a hack saw may be used to connect the cut 5 with the lower extremity of the skirt 4 and with the transverse cut 6; and to connect the apertures 4 with the transverse cut6. The piston is then ready to install in its cylinder.

Thus it will be seen that my new piston can be shipped partly finished with very little work required of the repair man beside the actual fitting needed with any partly finished piston.

The expanding ring higher up in the skirt overcomes much of the trouble due to too short engine cylinders. And the independent support by the piston head of the free ends of the skirt on either side of the longitudinal out, and the connection of the transverse cut with the apertures about the wrist pin lu s gives strength together with a flexibility right where it is needed most.

I am at present running one set of these pistons which were finished eight thousandths of an inch larger than the cylinder bore; the engine has more power than it has ever had before, can not be made to smoke, and runs most surprisingly cool, even under the hardest driving.

I have finished one of these pistons to the exact size of a cylinder, then put the piston on a stove till it was a dull red heat and then was able to push it into the cylinder, and later examination showed that it had touched the cylinder all the way round, and not at a few high spots only. From every test to date I feel that this piston is perfect.

Having now described my new piston, what I claim as new and desire to protect by Letters Patent, is as follows 1. A piston composed of a head section provided with a plurality of piston ring grooves and with wrist pin lugs rigidly integral therewith, a skirt section depending from said head section and separated by apertures from said wrist pin lugs and provided with a single longitudinal cut, the same side of the piston being provided with a transverse cut in connection with said longitudinal cut and connecting with said apertures, and means on either side of said longitudinal cut connecting said skirt with said head section.

2. A piston composed of a head section provided with wrist pin lugs rigidly integral therewith, a skirt section depending from said head section and separated from said wrist pin lugs by apertures for a partof their peripher and provided with a solid thrust face an roughly opposite thereto with a flexible thrust face provided with a single longitudinal cut and with a transverse cut in connection therewith and connecting with said apertures, and means connecting the flexible thrust face with the head section.

3. A piston composed of a head section with wrist pin lugs integral therewith, a skirt section depending from said head section and separated from said head section except upon one side and upon the other side provided with a longitudinal cut and with means con necting said other side of said skirt section with said head section.

4. A piston provided with a head section with wrist pin lugs integral therewith, a skirt section depending from said head section and attached thereto at only part of its periphery, and provided roughly opposite said part with a longitudinal cut and means on either side of said out connecting said skirt to said head section.

5. A piston composed of a head section with wrist pin lugs integral therewith. a skirt section depending fromsa-id head section and attached thereto at only part of its periphery, and provided roughly opposite said part with a longitudinal cut, means on either side of said cut connecting said skirt to said head section, and expanding means within said skirt section.

6. A piston composed of a head section with wrist pin lu integral therewith, a skirt section depending from said head section and attached thereto at only part of its periphery, and provided roughly opposite said part with a longitudinal out, means on lugs, and expanding means within said groove.

7. A piston provided with a head section a skirt section depending from said head section and attached thereto at only part of its periphery, the remaining part being provided with a longitudinal cut and means connecting said part to said head section.

8. A piston composed of a head section and a skirt section which is separated from said head section for a portion of its periphery and which portion is provided with a longitudinal cut and means connecting said portion with said head section.

9. A piston composed of a head section and a skirt section which is separated from said head section for a portion of its periphery and which portion is provided with a longitudinal out and means connecting said portion with said head section. and expanding means within said skirt section.

CHARLIE E. HATCH. 

